(3) DIFFERENCES IN SPATIOTEMPORAL VARIABLES AND JOINT ANGLES FOLLOWING RESISTED SPRINT TRAINING IN YOUTH ICE HOCKEY PLAYERS

Purpose: This study explored the impact of resisted sprint training (RST) on spatiotemporal variables and joint angles at toe-off (TO) and touchdown (TD) in male youth ice hockey players.

Methods: Twenty-four competitive youth ice hockey players participated in the study. Participants were separated into three equal groups (overground RST; on-ice RST; bodyweight training). Participants engaged in two sessions per week for a total of eight weeks. The bodyweight training program incorporated high-velocity body weight exercises. The load for RST was provided by sleds loaded with weight plates. At pre- and post-testing, participants completed two 30-meter acceleration maximal overground sprints. Video recordings of the sprint trials were obtained using a high-speed camera (iPad Air, Apple Inc., USA, 240 fps) placed at the 15-meter mark recording the participant from the sagittal plane. The video file was then imported into the Kinovea motion analysis software (Kinovea v0.9.5) to calculate spatiotemporal variables of interest (step length, step rate, contact time, and flight time) during the first complete step (TO to TD) taken within the 10-20-meter sprint distance. Joint angles of interest (trunk, hip, knee) at TO and TD during the first step taken within the 10-20-meter sprint distance were also obtained. Averages were used for statistical analysis. A repeated measures ANOVA with follow up analysis measured the differences in spatiotemporal variables and joint angles across groups and time point.

Results: There was a group by time point interaction effect for step rate (p=0.02; η²_p=0.33). Overground RST decreased step rate (Cohen’s d=-0.30; 95%CI [0.23,0.83]; p=0.02) whereas the on-ice RST group increased step rate (Cohen’s d= 0.40; 95%CI [0.18,0.99]; p= 0.02). There was a main effect of time point on contact time (p=0.03; η²_p =0.21). There were no interaction or main effects on step length or flight time (p >0.05). There was a main effect for time point on knee swing angle at TO (p=0.01; η²_p=0.29). There were no interaction or main effects on trunk angle at TO, hip swing leg angle at TO, hip stance leg angle at TO, and knee stance leg angle at TO (p >0.05). There was a group by time point interaction effect for trunk angle at TD (p=0.03, η²_p=0.31). Follow up analysis indicated overground RST increased trunk angle (Cohen’s d=1.45; 95%CI [0.07,2.86]; p=0.03). There was a main effect for time point on knee swing leg angle at TD (p< 0.01; η²_p=0.35), hip stance leg angle at TD (p< .001; η²_p=0.44), and knee stance leg angle at TD (p< 0.01; η²_p=0.32).

Conclusion: Step rate during overground sprinting decreased following overground RST yet increased following on-ice RST. Overground RST increased trunk angle at TD. Knee swing leg angle at TO and knee swing leg angle at TD increased following bodyweight and RST. Contact time, hip stance leg angle at TD and knee stance leg angle at TD decreased following bodyweight and RST. PRACTICAL APPLICATION: Coaches seeking to alter step rate and trunk angle during overground sprinting in ice hockey players may consider incorporating RST as a component of an ice hockey training program.

Acknowledgements: This abstract was derived from a study funded by the National Strength and Conditioning Association Foundation.